What is the difference between regenerative braking and friction braking in an Audi e-Tron?

I am curious about the different methods of braking used in electric vehicles and how they work in the Audi e-Tron specifically.

Regenerative braking is a way to capture the kinetic energy of a vehicle when it decelerates, and use it to charge the battery. In an Audi e-Tron, it is the primary form of braking.

Friction braking, on the other hand, is a more traditional method that uses brake pads to slow down the vehicle by creating friction with the wheels. It is mainly used in emergency situations or when the vehicle is moving at low speeds.